Oscillator-modulator circuit



Aug-y 14, 1945- w. DALLENACl- ETAL 8 OSCILLATOR-MODULATOR CIRCUIT Filed Feb. 24, 1941 2 Sheets-Sheet 1 SIG/VA 1. INPUT Ir I 65 I I FROM 1 I N I t HETERODVNE I IT OSCILLATOR a $23 IN T f RMED/A TE FREQUENCY OUTPUT SIGNAL INPUT m flER/IL 0 m 54 171761? aiuewam- Patented Aug. 14, 1945 2,382,693 osomLAToR- onULA'roR'oiRoUrr Walter Dallenbach, Berlin W 35; Alfred Allerding,

Berlin-Friedrichshagen, and Erich Huttmann,- Berlin-Kopenick, Germany; vested in the Alien Property Custodian Application February 24, 1941, Serial No. 380,368; In Germany February 24 1940 11 Claims. (c1.250'-'-20) 1 "Ihis invention relates to super-heterodyne receivers wherein the oscillator-and the aerial are coupled to the mixing tubein such a way that the oscillator-tube-will not radiate over the aerial. By mixing tube we refer to a tube in which the super-position and rectifying of two oscillations takes place.

The invention refers to a. device for super-position of two ultra-high frequency electro-fmagnetic systems of oscillations respectively for discoupling of two such systemsof oscillations, especially for application to super-heterodyne receiving apparatus. In. such case there can beused a Lecher-system .to which the one oscillation is led. The other conductor of this Lecher-system branches in two conductors which form a second Lecher-system to which the second oscillation is led. The arrangement of these two Lecher-systerns is made in such manner that the. twoconductors of the branching system oscillate in push-.

pull and both together work with 'respect to the other conductor of the first Lecher-system in the same rhythm j For a fuller description ofmy invention reference is made to the accompanying drawings.

Figure-1 shows a circuit which embodies the invention as applied to the reception of radio fre quencies generally. c

Figure 2 shows an arrangement which corre sponds to the general scheme of Fig. 1 and which at the same time shows the application of the invention to the special case of ultra-short waves. In this case the Lecher-systems are shown as comprising pipe-conductors I Figure 3 shows. the coupling of the two Lechersystems effected by the insertion of a currentloop of one Lecher system. into the magnetic field of the other Lecher-system, I a

Figure 4 shows the coupling being flmajde by means of a slot in the outer conductor of the one Lecher-system. p

Figs. 3a and 4a show cross sectional viewsof the arrangement of the Lecher-system taken on the lines 3a -3a and d'a'4a, respectively, of Figs. 3 and 4.

In Fig. 1 there is shown schematically a bridgenetwork. Atwo wire system 5, 5 carrying signal frequency from the aerial A is connected to a resonant circuit 6 consisting of capacity Ga and inductance 6b in parallel connection. From the resonant circuit 6 the conductors lead to the two blocking condensers land 1'' and from thereto the mixing tube as for example to the ano'des B and 8' of aduo-diode 23. Tothe centertap of the inductance 6b oft'he resonant circuit. Ii on.

one hand andto the cathode 9 of the duo' diode on the other hand there are connected thc'two' conductors [0, I0 of aLecher-system which lead: from an oscillator-tube. Furthermore the pri mary windings H. ll'of a push-pull trans;- former for the intermediate frequency are connected to the anodes 8 and 8". "The two windings II and llf are counterwoundfln order to pre vent the high frequency from flowing to the in termediate frequency transformer the two resonant circuits [land l2" are inserted in'the-con nection wires between the anodes 81 and 8' and the windings H and H". The thick lines in 'Fig'l indicate the c onductors of the high frequency cir'-' cuit while the thinlines show the conductors of the intermediate frequency circuit. f i e The ircuit shown in Fig. -1 acts-as follows? The energy'lines l0 and I'll lead from an oscillator which sets [up high; frequency oscillations and are connected to the bridge device; Both a-nodes 8 and 8 of the duo-diode oscillate in the same rhythm with respect to the cathode 9'. The high frequency current from the line 10 flows through iboth halves of the inductance of the resonant circuit 6, through t'hefblockingcondensers T, I, through 'the anodes 8 and 8, through the cath-; ode 9 ofithed uo diode'and from there back to the oscillator through theline" Ill. (The inductance of the parallel resonanc'ecircuit 6 can be com pensated by, a capacity in'the lead.) This high frequency current produces a direct currentflow from the cathode 9 of the duo-diode to the centre of the primary windings H, l l of the intermediate frequency transformer. A This direct current will. not produce any potential difference at the secondary'lwindings of the intermediate transformer, for both the halves of the windings II and II, are'counter-wound. Since equal currents flow from the c'. entr e'to-- the ends of the primary windings I l' and'll there will be no change of potential in thesec nd'ary windings. If on'the contrary there exists a high frequency voltage in the energy line 5, 5"leading from the aerial the anodes 8 and 8' cf the duo-diode will oscillate in push-pull. The currents which flow in theprimary winding l and l l of the transformer have the same 'direct'ion. Currents of this kind will not compensate each other with respect to the secondary windings but produce a direct current V e atthe terminals of the secondary wind:- ings. The high frequency current, coming from the aerial flows through wire 5 and blocking confdenser l to anode 8 of the duo-diode and from there tocathod'e ,SQWinding ill; and anode 8", and from there toblocking condenser '1 through the wire back to the aerial, or through wire 5 blocking condenser 1 anode 8 cathode 9, winding II, blocking condenser I, and wire 5 of the aerial circuit.

In Figure 2 an arrangement corresponding to the scheme of Fig. 1 is shown which is suitable for use in receiving ultra-short waves especially waves of a wave length less than 1 meter. The first Lecher-system comprises the conductors I and 2 which lead from the oscillator-tube. The conductor I branches into two conductors 3 and 4 at the point I3. These new conductors form a second Lecher-system consisting of two wires having a length of M2 or a multiple thereof. ()\=wave'length.) The system 3 and 4 is short circuited by a reflecting plate I4 constituting a bridging device. The conductors 3 and 4 form a resonator between I3 and I4 which, when excited, oscillates in push-pull. On the other hand, the conductor 2 may be connected to the plate I4 thereby establishing a potential node at this point for the Lecher-system I, 2. Thus it is seen that a high frequency oscillation is set up over the system 'I, 2 which produces a rhythmical oscillation f the conductors 3 and 4 together with respect to the conductor 2. The push-pull oscillations can.be set up by an opening I5 in the refleeting plate I4 with the aid of current coupling. The duo-diode is then connected near to a potential loop between the conductors 3 and 4, i. e. in a distance of M4 from the plate M in such manner that the anodes 8 and 8' and the blocking capacities I, I are connected with conductors 3 and 4 respectively while the cathode 9 is directly connected with conductor 2. The duo-diode tube presents an impedance which must be compensated, hence it will be found necessary to make the length of the conductors 3 and 4 not exactly M2 but of a length equivalent to M2 in such manner that the Lecher-system may be tuned to the desired wave length.

In Figure 3 the arrangement according to Fig. 2 is repeated except that in this case a concentrically formed Lecher-system is employed. The two conductors 3 and 4 are connected to the branching point I3 in form of a wire bridle in the same manner as shown in Figure 2. In order to illustrate the construction of this device more clearly a cross-section taken on the line 3a--3a of Fig. 3 locking in the-direction of the arrows is shown in Fig. 3a. The wires 3 and 4 are short circuited with the outer conductor 2 at I6 through capacity I1, so that the rhythmical 0scillation lead from I, 2 has a potential node at I6. A second concentric Lecher-system I4, I8 is arranged so that its outer conductor I4 serves as a reflector plate for the conductors 3 and 4. The

conductor I4 has an opening through which the conductors 3 and 4 project in form of a current loop I9 into the magnetic field f the Lechersystem I4, I8. In order to obtain a perfect symmetric coupling to the system I4, I8 in regard to the conductors 3 and 4 it is advantageous to provide the loop I 9 in a potential node of the Lecher-system I4, I8. The center of the 1001) I9 [has thus a distance of M2 01 a multiple thereof of the short-circuited end of the system I4, I8. From this follows that by such arrangement the aerial oscillation introduced at 2I causes no rhythmical oscillation at 22 and vice versa the oscillation of the oscillator-tube introduced at 22 causes no push-pull oscillation at 2I. This is a consequence of the symmetry of the arrangement. If when the device is placed under actual operating conditions it is found that symmetry is not preserved it can be restored with the aid of small trimming capacities connected between the conductors 3 and 4 n the one hand and the outer conductor 2 on the other hand.

Near to a potential loop of the system 3, 4 the anodes 8, 8 of the duo-diode 23 are coupled to the conductors 3 and 4 through the blocking condensers I and 'I' and the cathode 9 is connected to the jacket 2. The direct current can be drawn from the wires 24 which are arranged to be free of inductance and parallel to the conductors 3 and 4. They can run in the inner space of the hollow conductor I to the intermediate transformer.

Figure 4 shows another embodiment of the invention. Instead of a current loop I9 projecting into the magnetic field of the Lecher-system I4, I8 as shown in Figure 3 there is provided a slot 25 in the outer conductor I4 symmetrically with respect to the conductors 3 and 4, thereby eifecting a coupling between the Lecher-systems I4, I8 and 3, 4. The blocking condensers 26 and 26' may comprise concentric pipes insulated from the conductors 3 and 4. The anodes of the duodiode 23 are connected directly to these condensers. The pipes 26 and 26' also act as a second Lecher-system for they carry the push-pull oscillation as well as that of the conductors 3 and 4. The arrangement shown in Figure 4a is a crosssectional view along the line 4a-4a looking in the direction of the arrows. The wires 24 for the direct current are connected in a potential node to the blocking condensers 26 and 26 and are extended through and insulated from contact with the hollow conductor I and are connected to the intermediate frequency transformer by the wires 24.

It is advantageous as shown in all figures to provide the aerial-oscillation as push-pull oscillation and the oscillator oscillation as rhythmical oscillation for the push-pull oscillation needs no high frequency energy in the cathode conductors. These cathode conductors are advantageously made from thin wires in order to prevent heat losses which cause a strong damping effect on the weak aerial oscillations, On the other hand since the oscillator possesses a correspondingly large amount of energy the damping will not afiect it.

What we claim is:

1. A device for superposition of two ultra-highfrequency oscillations, comprising a Lecher-system to which one oscillation is led, one conductor of the said Lecher-system branching into two conductors forming a second Lecher-system to which the other oscillation is led, a. bridging device for said second Lecher-system said second Lecher-system oscillating with respect to the first Lecher-system in such manner that the two conductors of the branching system oscillate in pushpull with respect to said bridge device, and both together oscillate rhythmically with respect to the other conductor of the first Lecher-system.

2. A device for superposition of two ultrahigh-frequency oscillations, comprising a Lechersystem to which one oscillation is led, one conductor of the Lecher-system branching in two conductors forming a second Lecher-system to which the other oscillation is led', a bridging device for said second Leoher-system said second Lecher-system oscillating with respect to the first Lecher-system in such manner that the two conductors of the branching system oscillate in pushpull with respect to said bridge device, and both together oscillate rhythmically with respect to ductor of the Lecher-system branching in two conductors forming a second Lecher-system to which the other oscillation is led, a bridging device for said second Lecher-system, said second further concentric Lecher-system, coupling taking 'place in a potential node.

"7. A device for superposition of two ultrahigh-frequencyoscill'ations, comprising a Lechersystem to which the oscillation is led, one conductor of the Lecher-system branching into two node, said point having a distance of M2 from the branching point.

4. A device for superposition of two ultrahigh-frequency oscillations, comprising a Lechersystem to which one oscillation is led, one conductor of the Lecher-system branching in two conductors forming a second Lecher-system to which the other oscillation is led, a bridging device for said second Lecher-system said second Lecher-system oscillating in regard to the first Lecher-system in such manner that the two conductors of the branching system oscillate in push-pull with respect to said bridge device, and both together oscillate rhythmically with respect to the other conductor of the first Lecher-system, both Lecher-system being excited to push-pull oscillations by a slot formed in the short circuiting bridge and provided symmetrically to the two conductors of the second Lecher-system.

5. A device for superposition of two ultrahigh-frequency oscillations, comprising a Lechersystem to which the oscillation is led, one conductor of the Lecher-system branching in two conductors forming a second Lecher-system to which the other oscillation is led, a bridge device for said second Lecher-system, said second Lecher-system oscillating with respect to the first Lecher-system in such manner that the two conductors of the branching system oscillate in push-pull with respect to the said bridge device, and both together oscillate rhythmically with respect to the other conductor of the first Lechersystem, both Lecher-systems being excited to push-pull oscillations by a gap in the short cir-.

cuiting bridge, the two conductors of the second Lecher-system behind the bridge forming a current loop, coupling a, high frequency magnetic field.

6. A device for superposition of two ultrahigh-frequency oscillations, comprising a Lechersystem to which the oscillation is led, one conductor of the Lecher-system branching in two conductors forming a second Lecher-system to which the other oscillation is led, a bridge device for second Lecher-system, said second- Lecher-system oscillating with respect to the first Lecher-system in such manner that the two conductors of the branching system oscillate in push-pull with respect to the said bridge device, and both together oscillate rhythmically with respect to the other conductor of the first Lecher-system, both Lecher-systems being concentrically formed and being short-circuited by a bridge at the point of a joint potential node said bridge being formed by the outer conductor of a conductors forming a second Lecher-system to which-the other oscillation is led, a bridge device forsaid'second'Lecher-system said second Lecher-system oscillating with respect to the first Lecher-system in such manner that the two conductors of the branching system oscillate in push-pull with respect to the bridge device, and both together oscillate rhythmically in regard to the other conductor of the first Lecher-system, a potential loop formed by said second Lecher-system an impedance connected between both conductors of the second Lecher-system, the center of said impedance being connected with the other conductor of the first Lechersystem.

8. A device for superposition of two ultrahigh-frequency oscillations, comprising a Lechersystem to which the oscillation is led, one conductor of the Lecher-system branching into two conductors forming a second Lecher-system to which the other oscillation is led, a bridge device for said second Lecher-system said second Lecher-system oscillating with respect to the first Lecher-system in such manner that the two conductors of the branching system oscillate in push-pull with respect to said bridge device, and both together oscillate rhythmically with respect to the other conductor of the first Lecher-system, a potential loop formed by said second Lecher-system and an impedance comprising a duo-diode connected between the conductors of said second Lecher-system, the anodes of the duo-diode being connected through blocking condensers with the conductors of the second Lecher-system, the cathode being connected to the other conductor of the first Lecher-system.

9. A device for superposition of two ultrahigh-frequency oscillations, comprising a Lechersystem to which the oscillation is led, one conductor of the Lecher-system branching into two conductors forming a second Lecher-system to which the other oscillation is led, a bridge device for said second Lecher-system said second Lecher-system oscillating with respect to the first Lecher-system in such manner that the two conductors of the branching system oscillate in push-pull with respect to the said bridge device, and both together oscillate rhythmically with respect to the other conductor of the first Lecher-system, said push-pull oscillations being excited by an aerial, said rhythmical oscillations being excited by an oscillator.

10. A device for superposition of two ultrahigh-frequency oscillations, comprising a Lechersystem to which one oscillation is led, one conductor of the Lecher-system branching into two conductors forming a second Lecher-system to which the other oscillation is led, a bridge device for said second Lecher-system said second Lecher-system oscillatingwith respect to the first Lecher-system in such manner that the two conductors of the branching system oscillate in push-pull with respect to the bridge device, and both together oscillate rhythmically with respect to the other conductor of the first Lecher-system, near a potential loop formed by said second Lecher-system an impedance is connected between both conductors of the second Lecher-system, said impedance comprising a duo-diode, the

anodes-s being connected. through blocking jcoII- densers with the conductors of the second Lechersystem, the cathode being connected to the other conductor of the first Lecher system, said pushpull oscillations being excited by an aerial, said rhythmical oscillations being excited by an oscil1ator,-- the intermediate frequency being led free of inductance from the anodes of the duodiode to the; branching point and from .there alon the inner conductor-of the first Lecl ersystem to a push-pull transformer; the center of which is connected withthe'other conductor of the first Lecher-system. Y I

11. A device for the superposition of two ultrahigh frequency oscillations comprising a Lechersystem to which one oscillation is led, said Leoher-system being formed of an outer tubular conductor and an inner conductor, said inner conductor ;space d;from said outer; tubular conductor and concentric therewith branching into two conductors forming a second Lecher-system to which the other oscillation is led, a bridging device for said second Lecher-system, said second hecheresystem oscillating withrespect to said first'Lecher-systemin such a manner that the two conductors of I the branching system oscillate in push-pull with; respect to the said bridging device and :both together oscillate rhythmically with respecttothe outer conductor of the said first Lecher system, said inner conduc tor branching at a potential node for the push-pull oscillations.

DAILENBACH. ALFRED ALLERDIINGII ERICH l 

